This research proposal will involve studies in female rhesus monkeys after complete pituitary stalk section. The experiments will have two main objectives: 1. A detailed study of the extent of morphological and functional central neural regeneration which occurs after this surgical procedure. Morphological regeneration will be studied using specific immunohistochemical techniques for oxytocin, vasopressin, neurophysins I and II and gonadotropin-releasing hormone. The response of these hormones to specific tests will be studied using radioimmunoassay techniques. The possible factors initiating and promoting these regenerative processes will also be investigated. 2. Pituitary-stalk sectioned monkeys will also be used as models to study direct or modulatory effects on the pituitary by ovarian steroids and LH, FSH and prolactin secretion. Direct pituitary control of prolactin secretion by biogenic amines will also be studied. The results obtained from these experiments may reveal important aspects of central nervous system regeneration and may contribute significant knowledge on the independent role of the anterior pituitary gland in reproductive processes in primates.